[Dinosoar]

I am researching to get to the ground truth about GDI and intake valve carbon deposits with the B58. Looking to get 2020 M240.

Any one have any issues they know of? That is, you've looked (bore scope or disassemble). Or worse, had notable reduction in performance where a shop, then, said you have carbon on the intake valves and needed it walnut blasted it out (or similar)?

Help convert this Mustang driver to an M240i driver, please (I've had it with Ford)!

[dradernh]

Originally Posted by Dinosoar

Or...had notable reduction in performance

I asked a shop owner who would know about this, and he said a performance reduction wouldn't be the issue; instead, it would be a poor idle that would cause an owner to want to clean the valves.

[Dinosoar]

I'll assume one of two things, guys just aren't seeing carbon build up on their intake valves. Or, no one's noticed my thread but "dradernh"

The BMW Genius (really? the call it that) was super smart about BMW tech and told me they had a guy in with a B58 sensor issue that caused them to look at the intake valves. At 38K miles, they were spotless he said.

The explanation he gave was how BMW does their PCV routing. In short, he said they push it back to the crankcase, not the intake manifold. This was talking with the sales guy, so of course I am skeptical about the Genius' motives, right?

I think I've made my decision to trust BMW engineers (and the Genius) and start talking numbers with my sales guy. Just had enough drama with my Mustang and I've always loved BMW.

[kthor703]

Originally Posted by Dinosoar

I'll assume one of two things, guys just aren't seeing carbon build up on their intake valves. Or, no one's noticed my thread but "dradernh"

The BMW Genius (really? the call it that) was super smart about BMW tech and told me they had a guy in with a B58 sensor issue that caused them to look at the intake valves. At 38K miles, they were spotless he said.

The explanation he gave was how BMW does their PCV routing. In short, he said they push it back to the crankcase, not the intake manifold. This was talking with the sales guy, so of course I am skeptical about the Genius' motives, right?

I think I've made my decision to trust BMW engineers (and the Genius) and start talking numbers with my sales guy. Just had enough drama with my Mustang and I've always loved BMW.

My only comment about that explanation is the goal of the PCV (positive crankcase ventilation) is REMOVE pressure from the crankcase. It doesn't make sense that they would route it back...Not discounting the health of the valves though.

[MassNerd]

Most of the B58 chat happens over on the F30 forum as the engine appeared in that chassis first.
https://f30.bimmerpost.com/forums/se...61960190&pp=30

A quick search for carbon didn't turn up much in the way of reported issues. Just speculation of what might make it worse.

[amw896]

I dont believe the b58 has any carbon buildup issues. This was resolved even on the n55.

[dradernh]

Originally Posted by Dinosoar

I am researching to get to the ground truth about GDI and intake valve carbon deposits with the B58.

This event probably won't work for you as you're in the Mid-Atlantic region, but the Boston Chapter has an event a week from tomorrow that covers this very subject: http://www.boston-bmwcca.org/event/t...al-coke-habit/.

It's for the N55 motor (among others) and not the B58, but the general information provided at the session may well be applicable to our motors. Might be worth the trouble to call the shop to discuss.

If you learn anything worth sharing on the subject, please post it back to this thread (or start another one) so that we can find out more about where we stand on this potential issue.